Cook the pasta according to the package directions. Reserve 1 cup of the cooking water; drain.

Meanwhile, cook the bacon in a large skillet over medium heat, stirring occasionally, until beginning to crisp, 6 to 8 minutes. Add the onion, garlic, and ¼ teaspoon each salt and pepper. Cook, stirring occasionally, until the onion is soft, 6 to 8 minutes. Add the tomatoes and cook, stirring occasionally, until thickened, 8 to 10 minutes. Add the peas and cook until warmed through, 3 to 4 minutes.

Add the pasta, Parmesan, and ½ cup of the cooking water to the sauce and toss to coat. (Add more cooking water as needed to loosen the sauce.)